While exposure to second hand smoke isn't ideal, a weekend or two of it won't be a big deal in the long run...it's long-term exposure that does any real damage. Just try to keep it to a minimum, choose non-smoking areas where you can and try to get outside for some fresh air as often as possible.
I do sympathize with you having to deal with that, I forget that not everywhere is like here in BC, Canada where smoking is not allowed in any public places whatsoever. I almost forget what it was like to go out to a restaurant or bar and come out smelling like the inside of a cigarette pack!